import SwiftUI

struct MainTabView: View {
  @State private var selectedTab: Int = 0
  
  var body: some View {
    TabView(selection: $selectedTab) {
      FeedView()
        .tabItem {
          Label("Home", systemImage: "house.fill")
        }
        .tag(0)
      
      SettingsView()
        .tabItem {
          Label("Settings", systemImage: "gear")
        }
        .tag(1)
    }
  }
}

struct FeedView: View {
  @StateObject private var viewModel = FeedViewModel()
  
  var body: some View {
    NavigationStack {
      List(viewModel.items) { item in
        NavigationLink(destination: ItemDetail(item: item)) {
          FeedItemRow(item: item)
        }
      }
      .navigationTitle("Home")
    }
  }
}

struct SettingsView: View {
  @AppStorage("isDarkMode") var isDarkMode = false
  
  var body: some View {
    NavigationStack {
      List {
        Toggle("Dark Mode", isOn: $isDarkMode)
      }
      .navigationTitle("Settings")
    }
  }
}

KEY PATTERNS: Use @State for local tab selection. Separate views prevent re-renders. AppStorage connects settings to system persistence. NavigationStack replaces deprecated NavigationView - required for iOS 16+.